Global local.env files

Current every project has an local.env file. But a user cannot have a personal local.env equivalent file that can affect all projects, nor can a computer have a local.env equivalent that would affect every project on there.

Suggested order and names:

1. /etc/just_local.env or /usr/local/share/just/local.env not sure which is better. The first seems more right
2. ~/.just_local.env or ~/.config/just/local.env or ~/.local/share/just/local.env not sure which is better. The first two seem more right
3. {project}/local.env
4. {project}/{project}.env
5. /etc/just_local_post.env or /usr/local/share/just/local_post.env not sure which is better
6. ~/.just_local_post.env or ~/.config/just/local_post.env or ~/.local/share/just/local_post.env not sure which is better
7. {project}/local_post.env

The order is intentional, so the user can override the system, and the project can override the user/system, and always gets the last call

Start by locating the common scripts that currently load each project's local.env file. Review how environment files are discovered and ordered, then determine suitable system and user paths and implement the proposed precedence. Done means system, user, project, and post-environment files are consistently loaded in the stated order across projects.